From 25dcae299b77675eb1903113e3b3bd22851b2d2e Mon Sep 17 00:00:00 2001 From: Leto_b Date: Wed, 22 Apr 2026 17:14:33 +0800 Subject: [PATCH] add cte in table query from 2091 --- src/.vuepress/sidebar/V2.0.x/en-Table.ts | 1 + src/.vuepress/sidebar/V2.0.x/zh-Table.ts | 1 + .../sidebar_timecho/V2.0.x/en-Table.ts | 1 + .../sidebar_timecho/V2.0.x/zh-Table.ts | 1 + .../Common-Table-Expression_apache.md | 233 +++++++++++++++++ .../Common-Table-Expression_timecho.md | 233 +++++++++++++++++ .../Common-Table-Expression_apache.md | 233 +++++++++++++++++ .../Common-Table-Expression_timecho.md | 233 +++++++++++++++++ .../Common-Table-Expression_apache.md | 234 ++++++++++++++++++ .../Common-Table-Expression_timecho.md | 234 ++++++++++++++++++ .../Common-Table-Expression_apache.md | 234 ++++++++++++++++++ .../Common-Table-Expression_timecho.md | 234 ++++++++++++++++++ 12 files changed, 1872 insertions(+) create mode 100644 src/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_apache.md create mode 100644 src/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_timecho.md create mode 100644 src/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_apache.md create mode 100644 src/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_timecho.md create mode 100644 src/zh/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_apache.md create mode 100644 src/zh/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_timecho.md create mode 100644 src/zh/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_apache.md create mode 100644 src/zh/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_timecho.md diff --git a/src/.vuepress/sidebar/V2.0.x/en-Table.ts b/src/.vuepress/sidebar/V2.0.x/en-Table.ts index e148e6ef6..fd9b15424 100644 --- a/src/.vuepress/sidebar/V2.0.x/en-Table.ts +++ b/src/.vuepress/sidebar/V2.0.x/en-Table.ts @@ -233,6 +233,7 @@ export const enSidebar = { { text: 'ORDER BY Clause', link: 'OrderBy-Clause' }, { text: 'LIMIT&OFFSET Clause', link: 'Limit-Offset-Clause' }, { text: 'Nested Queries', link: 'Nested-Queries' }, + { text: 'Common Table Expressions (CTE)', link: 'Common-Table-Expression_apache' }, ], }, { text: 'Maintenance Statements', link: 'SQL-Maintenance-Statements_apache' }, diff --git a/src/.vuepress/sidebar/V2.0.x/zh-Table.ts b/src/.vuepress/sidebar/V2.0.x/zh-Table.ts index b66faad96..1f065e998 100644 --- a/src/.vuepress/sidebar/V2.0.x/zh-Table.ts +++ b/src/.vuepress/sidebar/V2.0.x/zh-Table.ts @@ -230,6 +230,7 @@ export const zhSidebar = { { text: 'ORDER BY子句', link: 'OrderBy-Clause' }, { text: 'LIMIT&OFFSET子句', link: 'Limit-Offset-Clause' }, { text: '嵌套查询', link: 'Nested-Queries' }, + { text: '公用表表达式（CTE）', link: 'Common-Table-Expression_apache' }, ], }, { text: '运维语句', link: 'SQL-Maintenance-Statements_apache' }, diff --git a/src/.vuepress/sidebar_timecho/V2.0.x/en-Table.ts b/src/.vuepress/sidebar_timecho/V2.0.x/en-Table.ts index 49272a093..0d75205aa 100644 --- a/src/.vuepress/sidebar_timecho/V2.0.x/en-Table.ts +++ b/src/.vuepress/sidebar_timecho/V2.0.x/en-Table.ts @@ -265,6 +265,7 @@ export const enSidebar = { { text: 'LIMIT&OFFSET Clause', link: 'Limit-Offset-Clause' }, { text: 'Nested Queries', link: 'Nested-Queries' }, { text: 'Pattern Query', link: 'Row-Pattern-Recognition_timecho' }, + { text: 'Common Table Expressions (CTE)', link: 'Common-Table-Expression_timecho' }, ], }, { text: 'Maintenance Statements', link: 'SQL-Maintenance-Statements_timecho' }, diff --git a/src/.vuepress/sidebar_timecho/V2.0.x/zh-Table.ts b/src/.vuepress/sidebar_timecho/V2.0.x/zh-Table.ts index 4400dcae3..c9bb2795f 100644 --- a/src/.vuepress/sidebar_timecho/V2.0.x/zh-Table.ts +++ b/src/.vuepress/sidebar_timecho/V2.0.x/zh-Table.ts @@ -256,6 +256,7 @@ export const zhSidebar = { { text: 'LIMIT&OFFSET子句', link: 'Limit-Offset-Clause' }, { text: '嵌套查询', link: 'Nested-Queries' }, { text: '模式查询', link: 'Row-Pattern-Recognition_timecho' }, + { text: '公用表表达式（CTE）', link: 'Common-Table-Expression_timecho' }, ], }, { text: '运维语句', link: 'SQL-Maintenance-Statements_timecho' }, diff --git a/src/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_apache.md b/src/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_apache.md new file mode 100644 index 000000000..1669764c2 --- /dev/null +++ b/src/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_apache.md @@ -0,0 +1,233 @@ + +# Common Table Expressions (CTE) + +## 1. Overview + +CTE (Common Table Expressions) supports defining one or more temporary result sets (called common tables) using the `WITH` clause. These result sets can be referenced multiple times in subsequent parts of the same query. CTE provides a clean way to construct complex queries, making SQL code more readable and maintainable. + +> Note: This feature is available since version 2.0.9-beta. + +## 2. Syntax Definition + +The simplified SQL syntax for CTE is as follows: + +```sql +with_clause: + WITH cte_name [(col_name [, col_name] ...)] AS (subquery) + [, cte_name [(col_name [, col_name] ...)] AS (subquery)] ... +``` + +- Supports simple and nested CTEs: One or more CTEs can be defined in a `WITH` clause, and CTEs can reference each other in a nested way (forward references are **not** allowed, meaning a CTE cannot reference another CTE that has not yet been defined). +- Name conflict between CTE and source table: If a CTE has the same name as a source table, only the CTE is visible in the outer scope, and the source table is shadowed. +- Multiple references to CTE: The same CTE can be referenced multiple times in the outer query. +- EXPLAIN / EXPLAIN ANALYZE support: `EXPLAIN` or `EXPLAIN ANALYZE` can be used on the entire query, but **not** on the `subquery` inside a CTE definition. +- Column count constraint: The number of column names specified in a CTE definition must match the number of output columns from the `subquery`, otherwise an error will be thrown. +- Unused CTE: A query can still execute normally if a defined CTE is not referenced in the main query body. + +## 3. Examples + +Using tables `table1` and `table2` from the [Sample Data](../Reference/Sample-Data.md) as source tables: + +### 3.1 Simple CTE + +```sql +WITH cte1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte2 AS (SELECT device_id, humidity FROM table2 WHERE humidity IS NOT NULL) +SELECT * FROM cte1 JOIN cte2 ON cte1.device_id = cte2.device_id LIMIT 10; +``` + +Result + +``` ++---------+-----------+---------+--------+ +|device_id|temperature|device_id|humidity| ++---------+-----------+---------+--------+ +| 100| 90.0| 100| 45.1| +| 100| 90.0| 100| 35.2| +| 100| 90.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 88.0| 100| 45.1| ++---------+-----------+---------+--------+ +Total line number = 10 +It costs 0.075s +``` + +### 3.2 CTE with the Same Name as Source Table + +```sql +WITH table1 AS (SELECT time, device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM table1 LIMIT 5; +``` + +Result + +``` ++-----------------------------+---------+-----------+ +| time|device_id|temperature| ++-----------------------------+---------+-----------+ +|2024-11-30T09:30:00.000+08:00| 101| 90.0| +|2024-11-30T14:30:00.000+08:00| 101| 90.0| +|2024-11-29T10:00:00.000+08:00| 101| 85.0| +|2024-11-27T16:39:00.000+08:00| 101| 85.0| +|2024-11-27T16:40:00.000+08:00| 101| 85.0| ++-----------------------------+---------+-----------+ +Total line number = 5 +It costs 0.103s +``` + +### 3.3 Nested CTE + +```sql +WITH + table1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte1 AS (SELECT device_id, temperature FROM table2 WHERE temperature IS NOT NULL), + table2 AS (SELECT temperature FROM table1), + cte2 AS (SELECT temperature FROM table1) +SELECT * FROM table2; +``` + +Result + +``` ++-----------+ +|temperature| ++-----------+ +| 90.0| +| 90.0| +| 85.0| +| 85.0| +| 85.0| +| 85.0| +| 90.0| +| 85.0| +| 85.0| +| 88.0| +| 90.0| +| 90.0| ++-----------+ +Total line number = 12 +It costs 0.050s +``` + +- Forward references are **not** supported + +```sql +WITH + cte2 AS (SELECT temperature FROM cte1), + cte1 AS (SELECT device_id, temperature FROM table1) +SELECT * FROM cte2; +``` + +Error message + +``` +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 550: Table 'database1.cte1' does not exist. +``` + +### 3.4 Multiple References to CTE + +```sql +WITH cte AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM cte WHERE temperature > (SELECT avg(temperature) FROM cte); +``` + +Result + +``` ++---------+-----------+ +|device_id|temperature| ++---------+-----------+ +| 101| 90.0| +| 101| 90.0| +| 100| 90.0| +| 100| 88.0| +| 100| 90.0| +| 100| 90.0| ++---------+-----------+ +Total line number = 6 +It costs 0.203s +``` + +### 3.5 EXPLAIN Support + +- Supported on the entire query + +```sql +EXPLAIN WITH cte AS (SELECT * FROM table1) SELECT * FROM cte; +``` + +Result + +``` ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| distribution plan| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │OutputNode-7 │ | +| │OutputColumns-[time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time] │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| │ | +| │ | +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │Collect-42 │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| ┌───────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┐ | +| │ │ | +| ┌───────────┐ ┌───────────┐ | +| │Exchange-49│ │Exchange-50│ | +| └───────────┘ └───────────┘ | +| │ │ | +| │ │ | +|┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐| +|│DeviceTableScanNode-41 │ │DeviceTableScanNode-40 │| +|│QualifiedTableName: database1.table1 │ │QualifiedTableName: database1.table1 │| +|│OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│| +|│DeviceNumber: 3 │ │DeviceNumber: 3 │| +|│ScanOrder: ASC │ │ScanOrder: ASC │| +|│PushDownOffset: 0 │ │PushDownOffset: 0 │| +|│PushDownLimit: 0 │ │PushDownLimit: 0 │| +|│PushDownLimitToEachDevice: false │ │PushDownLimitToEachDevice: false │| +|│RegionId: 2 │ │RegionId: 1 │| +|└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +Total line number = 29 +It costs 0.065s +``` + +- Not supported for internal queries of CTE + +```sql +WITH cte AS (EXPLAIN SELECT * FROM table1) SELECT * FROM cte; +``` + +Error message + +``` +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 700: line 1:14: mismatched input 'EXPLAIN'. Expecting: +``` \ No newline at end of file diff --git a/src/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_timecho.md b/src/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_timecho.md new file mode 100644 index 000000000..e2ae2ef06 --- /dev/null +++ b/src/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_timecho.md @@ -0,0 +1,233 @@ + +# Common Table Expressions (CTE) + +## 1. Overview + +CTE (Common Table Expressions) supports defining one or more temporary result sets (called common tables) using the `WITH` clause. These result sets can be referenced multiple times in subsequent parts of the same query. CTE provides a clean way to construct complex queries, making SQL code more readable and maintainable. + +> Note: This feature is available since version 2.0.9.1. + +## 2. Syntax Definition + +The simplified SQL syntax for CTE is as follows: + +```sql +with_clause: + WITH cte_name [(col_name [, col_name] ...)] AS (subquery) + [, cte_name [(col_name [, col_name] ...)] AS (subquery)] ... +``` + +- Supports simple and nested CTEs: One or more CTEs can be defined in a `WITH` clause, and CTEs can reference each other in a nested way (forward references are **not** allowed, meaning a CTE cannot reference another CTE that has not yet been defined). +- Name conflict between CTE and source table: If a CTE has the same name as a source table, only the CTE is visible in the outer scope, and the source table is shadowed. +- Multiple references to CTE: The same CTE can be referenced multiple times in the outer query. +- EXPLAIN / EXPLAIN ANALYZE support: `EXPLAIN` or `EXPLAIN ANALYZE` can be used on the entire query, but **not** on the `subquery` inside a CTE definition. +- Column count constraint: The number of column names specified in a CTE definition must match the number of output columns from the `subquery`, otherwise an error will be thrown. +- Unused CTE: A query can still execute normally if a defined CTE is not referenced in the main query body. + +## 3. Examples + +Using tables `table1` and `table2` from the [Sample Data](../Reference/Sample-Data.md) as source tables: + +### 3.1 Simple CTE + +```sql +WITH cte1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte2 AS (SELECT device_id, humidity FROM table2 WHERE humidity IS NOT NULL) +SELECT * FROM cte1 JOIN cte2 ON cte1.device_id = cte2.device_id LIMIT 10; +``` + +Result + +``` ++---------+-----------+---------+--------+ +|device_id|temperature|device_id|humidity| ++---------+-----------+---------+--------+ +| 100| 90.0| 100| 45.1| +| 100| 90.0| 100| 35.2| +| 100| 90.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 88.0| 100| 45.1| ++---------+-----------+---------+--------+ +Total line number = 10 +It costs 0.075s +``` + +### 3.2 CTE with the Same Name as Source Table + +```sql +WITH table1 AS (SELECT time, device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM table1 LIMIT 5; +``` + +Result + +``` ++-----------------------------+---------+-----------+ +| time|device_id|temperature| ++-----------------------------+---------+-----------+ +|2024-11-30T09:30:00.000+08:00| 101| 90.0| +|2024-11-30T14:30:00.000+08:00| 101| 90.0| +|2024-11-29T10:00:00.000+08:00| 101| 85.0| +|2024-11-27T16:39:00.000+08:00| 101| 85.0| +|2024-11-27T16:40:00.000+08:00| 101| 85.0| ++-----------------------------+---------+-----------+ +Total line number = 5 +It costs 0.103s +``` + +### 3.3 Nested CTE + +```sql +WITH + table1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte1 AS (SELECT device_id, temperature FROM table2 WHERE temperature IS NOT NULL), + table2 AS (SELECT temperature FROM table1), + cte2 AS (SELECT temperature FROM table1) +SELECT * FROM table2; +``` + +Result + +``` ++-----------+ +|temperature| ++-----------+ +| 90.0| +| 90.0| +| 85.0| +| 85.0| +| 85.0| +| 85.0| +| 90.0| +| 85.0| +| 85.0| +| 88.0| +| 90.0| +| 90.0| ++-----------+ +Total line number = 12 +It costs 0.050s +``` + +- Forward references are **not** supported + +```sql +WITH + cte2 AS (SELECT temperature FROM cte1), + cte1 AS (SELECT device_id, temperature FROM table1) +SELECT * FROM cte2; +``` + +Error message + +``` +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 550: Table 'database1.cte1' does not exist. +``` + +### 3.4 Multiple References to CTE + +```sql +WITH cte AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM cte WHERE temperature > (SELECT avg(temperature) FROM cte); +``` + +Result + +``` ++---------+-----------+ +|device_id|temperature| ++---------+-----------+ +| 101| 90.0| +| 101| 90.0| +| 100| 90.0| +| 100| 88.0| +| 100| 90.0| +| 100| 90.0| ++---------+-----------+ +Total line number = 6 +It costs 0.203s +``` + +### 3.5 EXPLAIN Support + +- Supported on the entire query + +```sql +EXPLAIN WITH cte AS (SELECT * FROM table1) SELECT * FROM cte; +``` + +Result + +``` ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| distribution plan| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │OutputNode-7 │ | +| │OutputColumns-[time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time] │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| │ | +| │ | +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │Collect-42 │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| ┌───────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┐ | +| │ │ | +| ┌───────────┐ ┌───────────┐ | +| │Exchange-49│ │Exchange-50│ | +| └───────────┘ └───────────┘ | +| │ │ | +| │ │ | +|┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐| +|│DeviceTableScanNode-41 │ │DeviceTableScanNode-40 │| +|│QualifiedTableName: database1.table1 │ │QualifiedTableName: database1.table1 │| +|│OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│| +|│DeviceNumber: 3 │ │DeviceNumber: 3 │| +|│ScanOrder: ASC │ │ScanOrder: ASC │| +|│PushDownOffset: 0 │ │PushDownOffset: 0 │| +|│PushDownLimit: 0 │ │PushDownLimit: 0 │| +|│PushDownLimitToEachDevice: false │ │PushDownLimitToEachDevice: false │| +|│RegionId: 2 │ │RegionId: 1 │| +|└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +Total line number = 29 +It costs 0.065s +``` + +- Not supported for internal queries of CTE + +```sql +WITH cte AS (EXPLAIN SELECT * FROM table1) SELECT * FROM cte; +``` + +Error message + +``` +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 700: line 1:14: mismatched input 'EXPLAIN'. Expecting: +``` \ No newline at end of file diff --git a/src/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_apache.md b/src/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_apache.md new file mode 100644 index 000000000..1669764c2 --- /dev/null +++ b/src/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_apache.md @@ -0,0 +1,233 @@ + +# Common Table Expressions (CTE) + +## 1. Overview + +CTE (Common Table Expressions) supports defining one or more temporary result sets (called common tables) using the `WITH` clause. These result sets can be referenced multiple times in subsequent parts of the same query. CTE provides a clean way to construct complex queries, making SQL code more readable and maintainable. + +> Note: This feature is available since version 2.0.9-beta. + +## 2. Syntax Definition + +The simplified SQL syntax for CTE is as follows: + +```sql +with_clause: + WITH cte_name [(col_name [, col_name] ...)] AS (subquery) + [, cte_name [(col_name [, col_name] ...)] AS (subquery)] ... +``` + +- Supports simple and nested CTEs: One or more CTEs can be defined in a `WITH` clause, and CTEs can reference each other in a nested way (forward references are **not** allowed, meaning a CTE cannot reference another CTE that has not yet been defined). +- Name conflict between CTE and source table: If a CTE has the same name as a source table, only the CTE is visible in the outer scope, and the source table is shadowed. +- Multiple references to CTE: The same CTE can be referenced multiple times in the outer query. +- EXPLAIN / EXPLAIN ANALYZE support: `EXPLAIN` or `EXPLAIN ANALYZE` can be used on the entire query, but **not** on the `subquery` inside a CTE definition. +- Column count constraint: The number of column names specified in a CTE definition must match the number of output columns from the `subquery`, otherwise an error will be thrown. +- Unused CTE: A query can still execute normally if a defined CTE is not referenced in the main query body. + +## 3. Examples + +Using tables `table1` and `table2` from the [Sample Data](../Reference/Sample-Data.md) as source tables: + +### 3.1 Simple CTE + +```sql +WITH cte1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte2 AS (SELECT device_id, humidity FROM table2 WHERE humidity IS NOT NULL) +SELECT * FROM cte1 JOIN cte2 ON cte1.device_id = cte2.device_id LIMIT 10; +``` + +Result + +``` ++---------+-----------+---------+--------+ +|device_id|temperature|device_id|humidity| ++---------+-----------+---------+--------+ +| 100| 90.0| 100| 45.1| +| 100| 90.0| 100| 35.2| +| 100| 90.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 88.0| 100| 45.1| ++---------+-----------+---------+--------+ +Total line number = 10 +It costs 0.075s +``` + +### 3.2 CTE with the Same Name as Source Table + +```sql +WITH table1 AS (SELECT time, device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM table1 LIMIT 5; +``` + +Result + +``` ++-----------------------------+---------+-----------+ +| time|device_id|temperature| ++-----------------------------+---------+-----------+ +|2024-11-30T09:30:00.000+08:00| 101| 90.0| +|2024-11-30T14:30:00.000+08:00| 101| 90.0| +|2024-11-29T10:00:00.000+08:00| 101| 85.0| +|2024-11-27T16:39:00.000+08:00| 101| 85.0| +|2024-11-27T16:40:00.000+08:00| 101| 85.0| ++-----------------------------+---------+-----------+ +Total line number = 5 +It costs 0.103s +``` + +### 3.3 Nested CTE + +```sql +WITH + table1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte1 AS (SELECT device_id, temperature FROM table2 WHERE temperature IS NOT NULL), + table2 AS (SELECT temperature FROM table1), + cte2 AS (SELECT temperature FROM table1) +SELECT * FROM table2; +``` + +Result + +``` ++-----------+ +|temperature| ++-----------+ +| 90.0| +| 90.0| +| 85.0| +| 85.0| +| 85.0| +| 85.0| +| 90.0| +| 85.0| +| 85.0| +| 88.0| +| 90.0| +| 90.0| ++-----------+ +Total line number = 12 +It costs 0.050s +``` + +- Forward references are **not** supported + +```sql +WITH + cte2 AS (SELECT temperature FROM cte1), + cte1 AS (SELECT device_id, temperature FROM table1) +SELECT * FROM cte2; +``` + +Error message + +``` +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 550: Table 'database1.cte1' does not exist. +``` + +### 3.4 Multiple References to CTE + +```sql +WITH cte AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM cte WHERE temperature > (SELECT avg(temperature) FROM cte); +``` + +Result + +``` ++---------+-----------+ +|device_id|temperature| ++---------+-----------+ +| 101| 90.0| +| 101| 90.0| +| 100| 90.0| +| 100| 88.0| +| 100| 90.0| +| 100| 90.0| ++---------+-----------+ +Total line number = 6 +It costs 0.203s +``` + +### 3.5 EXPLAIN Support + +- Supported on the entire query + +```sql +EXPLAIN WITH cte AS (SELECT * FROM table1) SELECT * FROM cte; +``` + +Result + +``` ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| distribution plan| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │OutputNode-7 │ | +| │OutputColumns-[time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time] │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| │ | +| │ | +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │Collect-42 │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| ┌───────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┐ | +| │ │ | +| ┌───────────┐ ┌───────────┐ | +| │Exchange-49│ │Exchange-50│ | +| └───────────┘ └───────────┘ | +| │ │ | +| │ │ | +|┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐| +|│DeviceTableScanNode-41 │ │DeviceTableScanNode-40 │| +|│QualifiedTableName: database1.table1 │ │QualifiedTableName: database1.table1 │| +|│OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│| +|│DeviceNumber: 3 │ │DeviceNumber: 3 │| +|│ScanOrder: ASC │ │ScanOrder: ASC │| +|│PushDownOffset: 0 │ │PushDownOffset: 0 │| +|│PushDownLimit: 0 │ │PushDownLimit: 0 │| +|│PushDownLimitToEachDevice: false │ │PushDownLimitToEachDevice: false │| +|│RegionId: 2 │ │RegionId: 1 │| +|└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +Total line number = 29 +It costs 0.065s +``` + +- Not supported for internal queries of CTE + +```sql +WITH cte AS (EXPLAIN SELECT * FROM table1) SELECT * FROM cte; +``` + +Error message + +``` +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 700: line 1:14: mismatched input 'EXPLAIN'. Expecting: +``` \ No newline at end of file diff --git a/src/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_timecho.md b/src/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_timecho.md new file mode 100644 index 000000000..e2ae2ef06 --- /dev/null +++ b/src/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_timecho.md @@ -0,0 +1,233 @@ + +# Common Table Expressions (CTE) + +## 1. Overview + +CTE (Common Table Expressions) supports defining one or more temporary result sets (called common tables) using the `WITH` clause. These result sets can be referenced multiple times in subsequent parts of the same query. CTE provides a clean way to construct complex queries, making SQL code more readable and maintainable. + +> Note: This feature is available since version 2.0.9.1. + +## 2. Syntax Definition + +The simplified SQL syntax for CTE is as follows: + +```sql +with_clause: + WITH cte_name [(col_name [, col_name] ...)] AS (subquery) + [, cte_name [(col_name [, col_name] ...)] AS (subquery)] ... +``` + +- Supports simple and nested CTEs: One or more CTEs can be defined in a `WITH` clause, and CTEs can reference each other in a nested way (forward references are **not** allowed, meaning a CTE cannot reference another CTE that has not yet been defined). +- Name conflict between CTE and source table: If a CTE has the same name as a source table, only the CTE is visible in the outer scope, and the source table is shadowed. +- Multiple references to CTE: The same CTE can be referenced multiple times in the outer query. +- EXPLAIN / EXPLAIN ANALYZE support: `EXPLAIN` or `EXPLAIN ANALYZE` can be used on the entire query, but **not** on the `subquery` inside a CTE definition. +- Column count constraint: The number of column names specified in a CTE definition must match the number of output columns from the `subquery`, otherwise an error will be thrown. +- Unused CTE: A query can still execute normally if a defined CTE is not referenced in the main query body. + +## 3. Examples + +Using tables `table1` and `table2` from the [Sample Data](../Reference/Sample-Data.md) as source tables: + +### 3.1 Simple CTE + +```sql +WITH cte1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte2 AS (SELECT device_id, humidity FROM table2 WHERE humidity IS NOT NULL) +SELECT * FROM cte1 JOIN cte2 ON cte1.device_id = cte2.device_id LIMIT 10; +``` + +Result + +``` ++---------+-----------+---------+--------+ +|device_id|temperature|device_id|humidity| ++---------+-----------+---------+--------+ +| 100| 90.0| 100| 45.1| +| 100| 90.0| 100| 35.2| +| 100| 90.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 88.0| 100| 45.1| ++---------+-----------+---------+--------+ +Total line number = 10 +It costs 0.075s +``` + +### 3.2 CTE with the Same Name as Source Table + +```sql +WITH table1 AS (SELECT time, device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM table1 LIMIT 5; +``` + +Result + +``` ++-----------------------------+---------+-----------+ +| time|device_id|temperature| ++-----------------------------+---------+-----------+ +|2024-11-30T09:30:00.000+08:00| 101| 90.0| +|2024-11-30T14:30:00.000+08:00| 101| 90.0| +|2024-11-29T10:00:00.000+08:00| 101| 85.0| +|2024-11-27T16:39:00.000+08:00| 101| 85.0| +|2024-11-27T16:40:00.000+08:00| 101| 85.0| ++-----------------------------+---------+-----------+ +Total line number = 5 +It costs 0.103s +``` + +### 3.3 Nested CTE + +```sql +WITH + table1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte1 AS (SELECT device_id, temperature FROM table2 WHERE temperature IS NOT NULL), + table2 AS (SELECT temperature FROM table1), + cte2 AS (SELECT temperature FROM table1) +SELECT * FROM table2; +``` + +Result + +``` ++-----------+ +|temperature| ++-----------+ +| 90.0| +| 90.0| +| 85.0| +| 85.0| +| 85.0| +| 85.0| +| 90.0| +| 85.0| +| 85.0| +| 88.0| +| 90.0| +| 90.0| ++-----------+ +Total line number = 12 +It costs 0.050s +``` + +- Forward references are **not** supported + +```sql +WITH + cte2 AS (SELECT temperature FROM cte1), + cte1 AS (SELECT device_id, temperature FROM table1) +SELECT * FROM cte2; +``` + +Error message + +``` +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 550: Table 'database1.cte1' does not exist. +``` + +### 3.4 Multiple References to CTE + +```sql +WITH cte AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM cte WHERE temperature > (SELECT avg(temperature) FROM cte); +``` + +Result + +``` ++---------+-----------+ +|device_id|temperature| ++---------+-----------+ +| 101| 90.0| +| 101| 90.0| +| 100| 90.0| +| 100| 88.0| +| 100| 90.0| +| 100| 90.0| ++---------+-----------+ +Total line number = 6 +It costs 0.203s +``` + +### 3.5 EXPLAIN Support + +- Supported on the entire query + +```sql +EXPLAIN WITH cte AS (SELECT * FROM table1) SELECT * FROM cte; +``` + +Result + +``` ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| distribution plan| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │OutputNode-7 │ | +| │OutputColumns-[time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time] │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| │ | +| │ | +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │Collect-42 │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| ┌───────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┐ | +| │ │ | +| ┌───────────┐ ┌───────────┐ | +| │Exchange-49│ │Exchange-50│ | +| └───────────┘ └───────────┘ | +| │ │ | +| │ │ | +|┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐| +|│DeviceTableScanNode-41 │ │DeviceTableScanNode-40 │| +|│QualifiedTableName: database1.table1 │ │QualifiedTableName: database1.table1 │| +|│OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│| +|│DeviceNumber: 3 │ │DeviceNumber: 3 │| +|│ScanOrder: ASC │ │ScanOrder: ASC │| +|│PushDownOffset: 0 │ │PushDownOffset: 0 │| +|│PushDownLimit: 0 │ │PushDownLimit: 0 │| +|│PushDownLimitToEachDevice: false │ │PushDownLimitToEachDevice: false │| +|│RegionId: 2 │ │RegionId: 1 │| +|└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +Total line number = 29 +It costs 0.065s +``` + +- Not supported for internal queries of CTE + +```sql +WITH cte AS (EXPLAIN SELECT * FROM table1) SELECT * FROM cte; +``` + +Error message + +``` +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 700: line 1:14: mismatched input 'EXPLAIN'. Expecting: +``` \ No newline at end of file diff --git a/src/zh/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_apache.md b/src/zh/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_apache.md new file mode 100644 index 000000000..28191c30a --- /dev/null +++ b/src/zh/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_apache.md @@ -0,0 +1,234 @@ + + +# 公用表表达式（CTE） + +## 1. 概述 + +CTE（Common Table Expressions，公用表表达式）功能支持通过 `WITH` 子句定义一个或多个临时结果集（即公用表），这些结果集可以在同一个查询的后续部分中被多次引用。CTE 提供了一种清晰的方式来构建复杂的查询，使 SQL 代码更易读和维护。 + +> 注意：该功能从 V2.0.9-beta 版本开始提供。 + +## 2. 语法定义 + +CTE 的简化 SQL 语法如下： + +```SQL +with_clause: + WITH cte_name [(col_name [, col_name] ...)] AS (subquery) + [, cte_name [(col_name [, col_name] ...)] AS (subquery)] ... +``` + +* 支持简单 CTE 和嵌套 CTE：可以在 `WITH` 子句中定义一个或多个 CTE，且 CTE 之间可以嵌套引用（但不能前向引用，即不能使用尚未定义的 CTE）。 +* CTE 名称与源表重名：如果 CTE 名称与源表重名，在外层作用域中只有 CTE 可见，源表将被屏蔽。 +* CTE 的多次引用：同一个 CTE 在外层查询中可以被多次引用。 +* Explain / ExplainAnalyze 支持：支持对整个查询进行 `Explain` 或 `ExplainAnalyze`，但不支持对 CTE 定义中的 `subquery` 进行 `Explain` 或 `ExplainAnalyze`。 +* 列名指定限制：CTE 定义时指定的列名个数需与 `subquery` 输出列个数一致，否则报错。 +* 未使用的 CTE：如果定义的 CTE 在查询主体中没有用到，查询仍可正常执行。 + +## 3. 使用示例 + +基于[示例数据](../Reference/Sample-Data.md) 中的表 `table1` 和 `table2`作为源表： + +### 3.1 简单 CTE + +```SQL +WITH cte1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte2 AS (SELECT device_id, humidity FROM table2 WHERE humidity IS NOT NULL) +SELECT * FROM cte1 join cte2 on cte1.device_id = cte2.device_id limit 10; +``` + +执行结果 + +```Bash ++---------+-----------+---------+--------+ +|device_id|temperature|device_id|humidity| ++---------+-----------+---------+--------+ +| 100| 90.0| 100| 45.1| +| 100| 90.0| 100| 35.2| +| 100| 90.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 88.0| 100| 45.1| ++---------+-----------+---------+--------+ +Total line number = 10 +It costs 0.075s +``` + +### 3.2 CTE 与源表重名 + +```SQL +WITH table1 AS (SELECT time, device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM table1 limit 5; +``` + +执行结果 + +```Bash ++-----------------------------+---------+-----------+ +| time|device_id|temperature| ++-----------------------------+---------+-----------+ +|2024-11-30T09:30:00.000+08:00| 101| 90.0| +|2024-11-30T14:30:00.000+08:00| 101| 90.0| +|2024-11-29T10:00:00.000+08:00| 101| 85.0| +|2024-11-27T16:39:00.000+08:00| 101| 85.0| +|2024-11-27T16:40:00.000+08:00| 101| 85.0| ++-----------------------------+---------+-----------+ +Total line number = 5 +It costs 0.103s +``` + +### 3.3 嵌套 CTE + +```SQL +WITH + table1 AS (select device_id, temperature from table1 WHERE temperature IS NOT NULL), + cte1 AS (select device_id, temperature from table2 WHERE temperature IS NOT NULL), + table2 AS (select temperature from table1), + cte2 AS (SELECT temperature FROM table1) +SELECT * FROM table2; +``` + +执行结果 + +```Bash ++-----------+ +|temperature| ++-----------+ +| 90.0| +| 90.0| +| 85.0| +| 85.0| +| 85.0| +| 85.0| +| 90.0| +| 85.0| +| 85.0| +| 88.0| +| 90.0| +| 90.0| ++-----------+ +Total line number = 12 +It costs 0.050s +``` + +* 不支持前向引用 + +```SQL +WITH + cte2 AS (SELECT temperature FROM cte1), + cte1 AS (select device_id, temperature from table1) +SELECT * FROM cte2; +``` + +错误信息 + +```Bash +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 550: Table 'database1.cte1' does not exist. +``` + +### 3.4 CTE 的多次引用 + +```SQL +WITH cte AS (select device_id, temperature from table1 WHERE temperature IS NOT NULL) +SELECT * FROM cte WHERE temperature > (SELECT avg(temperature ) FROM cte); +``` + +执行结果 + +```Bash ++---------+-----------+ +|device_id|temperature| ++---------+-----------+ +| 101| 90.0| +| 101| 90.0| +| 100| 90.0| +| 100| 88.0| +| 100| 90.0| +| 100| 90.0| ++---------+-----------+ +Total line number = 6 +It costs 0.241s +``` + +### 3.5 Explain 支持 + +* 支持整个查询 + +```SQL +EXPLAIN WITH cte AS (SELECT * FROM table1) SELECT * FROM cte; +``` + +执行结果 + +```Bash ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| distribution plan| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │OutputNode-7 │ | +| │OutputColumns-[time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time] │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| │ | +| │ | +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │Collect-42 │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| ┌───────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┐ | +| │ │ | +| ┌───────────┐ ┌───────────┐ | +| │Exchange-49│ │Exchange-50│ | +| └───────────┘ └───────────┘ | +| │ │ | +| │ │ | +|┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐| +|│DeviceTableScanNode-41 │ │DeviceTableScanNode-40 │| +|│QualifiedTableName: database1.table1 │ │QualifiedTableName: database1.table1 │| +|│OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│| +|│DeviceNumber: 3 │ │DeviceNumber: 3 │| +|│ScanOrder: ASC │ │ScanOrder: ASC │| +|│PushDownOffset: 0 │ │PushDownOffset: 0 │| +|│PushDownLimit: 0 │ │PushDownLimit: 0 │| +|│PushDownLimitToEachDevice: false │ │PushDownLimitToEachDevice: false │| +|│RegionId: 2 │ │RegionId: 1 │| +|└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +Total line number = 29 +It costs 0.065s +``` + +* 不支持 cte 内部查询 + +```SQL +WITH cte AS (EXPLAIN SELECT * FROM table1) SELECT * FROM cte; +``` + +错误信息 + +```Bash +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 700: line 1:14: mismatched input 'EXPLAIN'. Expecting: +``` diff --git a/src/zh/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_timecho.md b/src/zh/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_timecho.md new file mode 100644 index 000000000..b3dc653b2 --- /dev/null +++ b/src/zh/UserGuide/Master/Table/SQL-Manual/Common-Table-Expression_timecho.md @@ -0,0 +1,234 @@ + + +# 公用表表达式（CTE） + +## 1. 概述 + +CTE（Common Table Expressions，公用表表达式）功能支持通过 `WITH` 子句定义一个或多个临时结果集（即公用表），这些结果集可以在同一个查询的后续部分中被多次引用。CTE 提供了一种清晰的方式来构建复杂的查询，使 SQL 代码更易读和维护。 + +> 注意：该功能从 V 2.0.9.1 版本开始提供。 + +## 2. 语法定义 + +CTE 的简化 SQL 语法如下： + +```SQL +with_clause: + WITH cte_name [(col_name [, col_name] ...)] AS (subquery) + [, cte_name [(col_name [, col_name] ...)] AS (subquery)] ... +``` + +* 支持简单 CTE 和嵌套 CTE：可以在 `WITH` 子句中定义一个或多个 CTE，且 CTE 之间可以嵌套引用（但不能前向引用，即不能使用尚未定义的 CTE）。 +* CTE 名称与源表重名：如果 CTE 名称与源表重名，在外层作用域中只有 CTE 可见，源表将被屏蔽。 +* CTE 的多次引用：同一个 CTE 在外层查询中可以被多次引用。 +* Explain / ExplainAnalyze 支持：支持对整个查询进行 `Explain` 或 `ExplainAnalyze`，但不支持对 CTE 定义中的 `subquery` 进行 `Explain` 或 `ExplainAnalyze`。 +* 列名指定限制：CTE 定义时指定的列名个数需与 `subquery` 输出列个数一致，否则报错。 +* 未使用的 CTE：如果定义的 CTE 在查询主体中没有用到，查询仍可正常执行。 + +## 3. 使用示例 + +基于[示例数据](../Reference/Sample-Data.md) 中的表 `table1` 和 `table2`作为源表： + +### 3.1 简单 CTE + +```SQL +WITH cte1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte2 AS (SELECT device_id, humidity FROM table2 WHERE humidity IS NOT NULL) +SELECT * FROM cte1 join cte2 on cte1.device_id = cte2.device_id limit 10; +``` + +执行结果 + +```Bash ++---------+-----------+---------+--------+ +|device_id|temperature|device_id|humidity| ++---------+-----------+---------+--------+ +| 100| 90.0| 100| 45.1| +| 100| 90.0| 100| 35.2| +| 100| 90.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 88.0| 100| 45.1| ++---------+-----------+---------+--------+ +Total line number = 10 +It costs 0.075s +``` + +### 3.2 CTE 与源表重名 + +```SQL +WITH table1 AS (SELECT time, device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM table1 limit 5; +``` + +执行结果 + +```Bash ++-----------------------------+---------+-----------+ +| time|device_id|temperature| ++-----------------------------+---------+-----------+ +|2024-11-30T09:30:00.000+08:00| 101| 90.0| +|2024-11-30T14:30:00.000+08:00| 101| 90.0| +|2024-11-29T10:00:00.000+08:00| 101| 85.0| +|2024-11-27T16:39:00.000+08:00| 101| 85.0| +|2024-11-27T16:40:00.000+08:00| 101| 85.0| ++-----------------------------+---------+-----------+ +Total line number = 5 +It costs 0.103s +``` + +### 3.3 嵌套 CTE + +```SQL +WITH + table1 AS (select device_id, temperature from table1 WHERE temperature IS NOT NULL), + cte1 AS (select device_id, temperature from table2 WHERE temperature IS NOT NULL), + table2 AS (select temperature from table1), + cte2 AS (SELECT temperature FROM table1) +SELECT * FROM table2; +``` + +执行结果 + +```Bash ++-----------+ +|temperature| ++-----------+ +| 90.0| +| 90.0| +| 85.0| +| 85.0| +| 85.0| +| 85.0| +| 90.0| +| 85.0| +| 85.0| +| 88.0| +| 90.0| +| 90.0| ++-----------+ +Total line number = 12 +It costs 0.050s +``` + +* 不支持前向引用 + +```SQL +WITH + cte2 AS (SELECT temperature FROM cte1), + cte1 AS (select device_id, temperature from table1) +SELECT * FROM cte2; +``` + +错误信息 + +```Bash +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 550: Table 'database1.cte1' does not exist. +``` + +### 3.4 CTE 的多次引用 + +```SQL +WITH cte AS (select device_id, temperature from table1 WHERE temperature IS NOT NULL) +SELECT * FROM cte WHERE temperature > (SELECT avg(temperature ) FROM cte); +``` + +执行结果 + +```Bash ++---------+-----------+ +|device_id|temperature| ++---------+-----------+ +| 101| 90.0| +| 101| 90.0| +| 100| 90.0| +| 100| 88.0| +| 100| 90.0| +| 100| 90.0| ++---------+-----------+ +Total line number = 6 +It costs 0.241s +``` + +### 3.5 Explain 支持 + +* 支持整个查询 + +```SQL +EXPLAIN WITH cte AS (SELECT * FROM table1) SELECT * FROM cte; +``` + +执行结果 + +```Bash ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| distribution plan| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │OutputNode-7 │ | +| │OutputColumns-[time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time] │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| │ | +| │ | +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │Collect-42 │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| ┌───────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┐ | +| │ │ | +| ┌───────────┐ ┌───────────┐ | +| │Exchange-49│ │Exchange-50│ | +| └───────────┘ └───────────┘ | +| │ │ | +| │ │ | +|┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐| +|│DeviceTableScanNode-41 │ │DeviceTableScanNode-40 │| +|│QualifiedTableName: database1.table1 │ │QualifiedTableName: database1.table1 │| +|│OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│| +|│DeviceNumber: 3 │ │DeviceNumber: 3 │| +|│ScanOrder: ASC │ │ScanOrder: ASC │| +|│PushDownOffset: 0 │ │PushDownOffset: 0 │| +|│PushDownLimit: 0 │ │PushDownLimit: 0 │| +|│PushDownLimitToEachDevice: false │ │PushDownLimitToEachDevice: false │| +|│RegionId: 2 │ │RegionId: 1 │| +|└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +Total line number = 29 +It costs 0.065s +``` + +* 不支持 cte 内部查询 + +```SQL +WITH cte AS (EXPLAIN SELECT * FROM table1) SELECT * FROM cte; +``` + +错误信息 + +```Bash +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 700: line 1:14: mismatched input 'EXPLAIN'. Expecting: +``` diff --git a/src/zh/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_apache.md b/src/zh/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_apache.md new file mode 100644 index 000000000..28191c30a --- /dev/null +++ b/src/zh/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_apache.md @@ -0,0 +1,234 @@ + + +# 公用表表达式（CTE） + +## 1. 概述 + +CTE（Common Table Expressions，公用表表达式）功能支持通过 `WITH` 子句定义一个或多个临时结果集（即公用表），这些结果集可以在同一个查询的后续部分中被多次引用。CTE 提供了一种清晰的方式来构建复杂的查询，使 SQL 代码更易读和维护。 + +> 注意：该功能从 V2.0.9-beta 版本开始提供。 + +## 2. 语法定义 + +CTE 的简化 SQL 语法如下： + +```SQL +with_clause: + WITH cte_name [(col_name [, col_name] ...)] AS (subquery) + [, cte_name [(col_name [, col_name] ...)] AS (subquery)] ... +``` + +* 支持简单 CTE 和嵌套 CTE：可以在 `WITH` 子句中定义一个或多个 CTE，且 CTE 之间可以嵌套引用（但不能前向引用，即不能使用尚未定义的 CTE）。 +* CTE 名称与源表重名：如果 CTE 名称与源表重名，在外层作用域中只有 CTE 可见，源表将被屏蔽。 +* CTE 的多次引用：同一个 CTE 在外层查询中可以被多次引用。 +* Explain / ExplainAnalyze 支持：支持对整个查询进行 `Explain` 或 `ExplainAnalyze`，但不支持对 CTE 定义中的 `subquery` 进行 `Explain` 或 `ExplainAnalyze`。 +* 列名指定限制：CTE 定义时指定的列名个数需与 `subquery` 输出列个数一致，否则报错。 +* 未使用的 CTE：如果定义的 CTE 在查询主体中没有用到，查询仍可正常执行。 + +## 3. 使用示例 + +基于[示例数据](../Reference/Sample-Data.md) 中的表 `table1` 和 `table2`作为源表： + +### 3.1 简单 CTE + +```SQL +WITH cte1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte2 AS (SELECT device_id, humidity FROM table2 WHERE humidity IS NOT NULL) +SELECT * FROM cte1 join cte2 on cte1.device_id = cte2.device_id limit 10; +``` + +执行结果 + +```Bash ++---------+-----------+---------+--------+ +|device_id|temperature|device_id|humidity| ++---------+-----------+---------+--------+ +| 100| 90.0| 100| 45.1| +| 100| 90.0| 100| 35.2| +| 100| 90.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 88.0| 100| 45.1| ++---------+-----------+---------+--------+ +Total line number = 10 +It costs 0.075s +``` + +### 3.2 CTE 与源表重名 + +```SQL +WITH table1 AS (SELECT time, device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM table1 limit 5; +``` + +执行结果 + +```Bash ++-----------------------------+---------+-----------+ +| time|device_id|temperature| ++-----------------------------+---------+-----------+ +|2024-11-30T09:30:00.000+08:00| 101| 90.0| +|2024-11-30T14:30:00.000+08:00| 101| 90.0| +|2024-11-29T10:00:00.000+08:00| 101| 85.0| +|2024-11-27T16:39:00.000+08:00| 101| 85.0| +|2024-11-27T16:40:00.000+08:00| 101| 85.0| ++-----------------------------+---------+-----------+ +Total line number = 5 +It costs 0.103s +``` + +### 3.3 嵌套 CTE + +```SQL +WITH + table1 AS (select device_id, temperature from table1 WHERE temperature IS NOT NULL), + cte1 AS (select device_id, temperature from table2 WHERE temperature IS NOT NULL), + table2 AS (select temperature from table1), + cte2 AS (SELECT temperature FROM table1) +SELECT * FROM table2; +``` + +执行结果 + +```Bash ++-----------+ +|temperature| ++-----------+ +| 90.0| +| 90.0| +| 85.0| +| 85.0| +| 85.0| +| 85.0| +| 90.0| +| 85.0| +| 85.0| +| 88.0| +| 90.0| +| 90.0| ++-----------+ +Total line number = 12 +It costs 0.050s +``` + +* 不支持前向引用 + +```SQL +WITH + cte2 AS (SELECT temperature FROM cte1), + cte1 AS (select device_id, temperature from table1) +SELECT * FROM cte2; +``` + +错误信息 + +```Bash +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 550: Table 'database1.cte1' does not exist. +``` + +### 3.4 CTE 的多次引用 + +```SQL +WITH cte AS (select device_id, temperature from table1 WHERE temperature IS NOT NULL) +SELECT * FROM cte WHERE temperature > (SELECT avg(temperature ) FROM cte); +``` + +执行结果 + +```Bash ++---------+-----------+ +|device_id|temperature| ++---------+-----------+ +| 101| 90.0| +| 101| 90.0| +| 100| 90.0| +| 100| 88.0| +| 100| 90.0| +| 100| 90.0| ++---------+-----------+ +Total line number = 6 +It costs 0.241s +``` + +### 3.5 Explain 支持 + +* 支持整个查询 + +```SQL +EXPLAIN WITH cte AS (SELECT * FROM table1) SELECT * FROM cte; +``` + +执行结果 + +```Bash ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| distribution plan| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │OutputNode-7 │ | +| │OutputColumns-[time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time] │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| │ | +| │ | +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │Collect-42 │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| ┌───────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┐ | +| │ │ | +| ┌───────────┐ ┌───────────┐ | +| │Exchange-49│ │Exchange-50│ | +| └───────────┘ └───────────┘ | +| │ │ | +| │ │ | +|┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐| +|│DeviceTableScanNode-41 │ │DeviceTableScanNode-40 │| +|│QualifiedTableName: database1.table1 │ │QualifiedTableName: database1.table1 │| +|│OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│| +|│DeviceNumber: 3 │ │DeviceNumber: 3 │| +|│ScanOrder: ASC │ │ScanOrder: ASC │| +|│PushDownOffset: 0 │ │PushDownOffset: 0 │| +|│PushDownLimit: 0 │ │PushDownLimit: 0 │| +|│PushDownLimitToEachDevice: false │ │PushDownLimitToEachDevice: false │| +|│RegionId: 2 │ │RegionId: 1 │| +|└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +Total line number = 29 +It costs 0.065s +``` + +* 不支持 cte 内部查询 + +```SQL +WITH cte AS (EXPLAIN SELECT * FROM table1) SELECT * FROM cte; +``` + +错误信息 + +```Bash +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 700: line 1:14: mismatched input 'EXPLAIN'. Expecting: +``` diff --git a/src/zh/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_timecho.md b/src/zh/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_timecho.md new file mode 100644 index 000000000..b3dc653b2 --- /dev/null +++ b/src/zh/UserGuide/latest-Table/SQL-Manual/Common-Table-Expression_timecho.md @@ -0,0 +1,234 @@ + + +# 公用表表达式（CTE） + +## 1. 概述 + +CTE（Common Table Expressions，公用表表达式）功能支持通过 `WITH` 子句定义一个或多个临时结果集（即公用表），这些结果集可以在同一个查询的后续部分中被多次引用。CTE 提供了一种清晰的方式来构建复杂的查询，使 SQL 代码更易读和维护。 + +> 注意：该功能从 V 2.0.9.1 版本开始提供。 + +## 2. 语法定义 + +CTE 的简化 SQL 语法如下： + +```SQL +with_clause: + WITH cte_name [(col_name [, col_name] ...)] AS (subquery) + [, cte_name [(col_name [, col_name] ...)] AS (subquery)] ... +``` + +* 支持简单 CTE 和嵌套 CTE：可以在 `WITH` 子句中定义一个或多个 CTE，且 CTE 之间可以嵌套引用（但不能前向引用，即不能使用尚未定义的 CTE）。 +* CTE 名称与源表重名：如果 CTE 名称与源表重名，在外层作用域中只有 CTE 可见，源表将被屏蔽。 +* CTE 的多次引用：同一个 CTE 在外层查询中可以被多次引用。 +* Explain / ExplainAnalyze 支持：支持对整个查询进行 `Explain` 或 `ExplainAnalyze`，但不支持对 CTE 定义中的 `subquery` 进行 `Explain` 或 `ExplainAnalyze`。 +* 列名指定限制：CTE 定义时指定的列名个数需与 `subquery` 输出列个数一致，否则报错。 +* 未使用的 CTE：如果定义的 CTE 在查询主体中没有用到，查询仍可正常执行。 + +## 3. 使用示例 + +基于[示例数据](../Reference/Sample-Data.md) 中的表 `table1` 和 `table2`作为源表： + +### 3.1 简单 CTE + +```SQL +WITH cte1 AS (SELECT device_id, temperature FROM table1 WHERE temperature IS NOT NULL), + cte2 AS (SELECT device_id, humidity FROM table2 WHERE humidity IS NOT NULL) +SELECT * FROM cte1 join cte2 on cte1.device_id = cte2.device_id limit 10; +``` + +执行结果 + +```Bash ++---------+-----------+---------+--------+ +|device_id|temperature|device_id|humidity| ++---------+-----------+---------+--------+ +| 100| 90.0| 100| 45.1| +| 100| 90.0| 100| 35.2| +| 100| 90.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 85.0| 100| 45.1| +| 100| 85.0| 100| 35.2| +| 100| 85.0| 100| 35.1| +| 100| 88.0| 100| 45.1| ++---------+-----------+---------+--------+ +Total line number = 10 +It costs 0.075s +``` + +### 3.2 CTE 与源表重名 + +```SQL +WITH table1 AS (SELECT time, device_id, temperature FROM table1 WHERE temperature IS NOT NULL) +SELECT * FROM table1 limit 5; +``` + +执行结果 + +```Bash ++-----------------------------+---------+-----------+ +| time|device_id|temperature| ++-----------------------------+---------+-----------+ +|2024-11-30T09:30:00.000+08:00| 101| 90.0| +|2024-11-30T14:30:00.000+08:00| 101| 90.0| +|2024-11-29T10:00:00.000+08:00| 101| 85.0| +|2024-11-27T16:39:00.000+08:00| 101| 85.0| +|2024-11-27T16:40:00.000+08:00| 101| 85.0| ++-----------------------------+---------+-----------+ +Total line number = 5 +It costs 0.103s +``` + +### 3.3 嵌套 CTE + +```SQL +WITH + table1 AS (select device_id, temperature from table1 WHERE temperature IS NOT NULL), + cte1 AS (select device_id, temperature from table2 WHERE temperature IS NOT NULL), + table2 AS (select temperature from table1), + cte2 AS (SELECT temperature FROM table1) +SELECT * FROM table2; +``` + +执行结果 + +```Bash ++-----------+ +|temperature| ++-----------+ +| 90.0| +| 90.0| +| 85.0| +| 85.0| +| 85.0| +| 85.0| +| 90.0| +| 85.0| +| 85.0| +| 88.0| +| 90.0| +| 90.0| ++-----------+ +Total line number = 12 +It costs 0.050s +``` + +* 不支持前向引用 + +```SQL +WITH + cte2 AS (SELECT temperature FROM cte1), + cte1 AS (select device_id, temperature from table1) +SELECT * FROM cte2; +``` + +错误信息 + +```Bash +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 550: Table 'database1.cte1' does not exist. +``` + +### 3.4 CTE 的多次引用 + +```SQL +WITH cte AS (select device_id, temperature from table1 WHERE temperature IS NOT NULL) +SELECT * FROM cte WHERE temperature > (SELECT avg(temperature ) FROM cte); +``` + +执行结果 + +```Bash ++---------+-----------+ +|device_id|temperature| ++---------+-----------+ +| 101| 90.0| +| 101| 90.0| +| 100| 90.0| +| 100| 88.0| +| 100| 90.0| +| 100| 90.0| ++---------+-----------+ +Total line number = 6 +It costs 0.241s +``` + +### 3.5 Explain 支持 + +* 支持整个查询 + +```SQL +EXPLAIN WITH cte AS (SELECT * FROM table1) SELECT * FROM cte; +``` + +执行结果 + +```Bash ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| distribution plan| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │OutputNode-7 │ | +| │OutputColumns-[time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time] │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| │ | +| │ | +| ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ | +| │Collect-42 │ | +| │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ | +| └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ | +| ┌───────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┐ | +| │ │ | +| ┌───────────┐ ┌───────────┐ | +| │Exchange-49│ │Exchange-50│ | +| └───────────┘ └───────────┘ | +| │ │ | +| │ │ | +|┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐| +|│DeviceTableScanNode-41 │ │DeviceTableScanNode-40 │| +|│QualifiedTableName: database1.table1 │ │QualifiedTableName: database1.table1 │| +|│OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│ │OutputSymbols: [time, region, plant_id, device_id, model_id, maintenance, temperature, humidity, status, arrival_time]│| +|│DeviceNumber: 3 │ │DeviceNumber: 3 │| +|│ScanOrder: ASC │ │ScanOrder: ASC │| +|│PushDownOffset: 0 │ │PushDownOffset: 0 │| +|│PushDownLimit: 0 │ │PushDownLimit: 0 │| +|│PushDownLimitToEachDevice: false │ │PushDownLimitToEachDevice: false │| +|│RegionId: 2 │ │RegionId: 1 │| +|└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘| ++-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ +Total line number = 29 +It costs 0.065s +``` + +* 不支持 cte 内部查询 + +```SQL +WITH cte AS (EXPLAIN SELECT * FROM table1) SELECT * FROM cte; +``` + +错误信息 + +```Bash +Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 700: line 1:14: mismatched input 'EXPLAIN'. Expecting: +```